This invention relates to apparatus for cleaning swimming pools, and more particularly, to water delivery assemblies mounted at the inner surface of the pool for directing streams of water across the surface to loosen deleterious material from the surface and place it in suspension so it can be carried through the pool outlets to the cleaning filter.
The invention further relates to that class of pool cleaning apparatus in which the water delivery assemblies include rotatably and retractably mounted nozzle heads housed in a pool wall. When supplied with water under pressure, each nozzle head moves to an extended, active, position exposing nozzle passageways which eject jets of water across the surface of the pool. This is sometimes referred to as a "pop-up nozzle". The construction of the nozzle head is such that the reaction from the jet stream causes partial rotation of the head as it moves from its retracted to its extended position. Such rotation is random so that with each activation of the nozzle, a different arcuate region of the pool surface surrounding the nozzle is swept by the jet of water. Eventually, through successive operations, the entire area surrounding the nozzle is swept.
U.S. Pat. No. 3,521,304 entitled "Swimming Pool Cleaning System" granted July 21, 1970 to G. J. Ghiz and U.S. Pat. No. 3,675,252, entitled "Pop-up Head for Water Jet Pool Cleaning System" granted July 11, 1972 to G. J. Ghiz, disclose pool cleaning systems employing rotating nozzles for directing water jets across the interior surface of the pool structure for cleaning the surface. A pool cleaning system employing intermittently actuated pop-up type nozzles is disclosed in U.S. Pat. No. 4,212,088 entitled "Apparatus for Cleaning Swimming Pools" granted July 15, 1980 to J. M. Goettl and G. J. Ghiz. A similar system with a somewhat different pop-up nozzle is disclosed in U.S. Pat. No. 4,188,673 entitled "Rotatable Pop-Up Water Delivery Head for Pool Cleaning Systems," granted Feb. 19, 1980 to H. L. Carter.